Problem: On the way to school, Karen became fixated on the puzzle game on her phone!

<image>

The game is played as follows. In each level, you have a grid with n rows and m columns. Each cell originally contains the number 0.

One move consists of choosing one row or column, and adding 1 to all of the cells in that row or column.

To win the level, after all the moves, the number in the cell at the i-th row and j-th column should be equal to gi, j.

Karen is stuck on one level, and wants to know a way to beat this level using the minimum number of moves. Please, help her with this task!

Input

The first line of input contains two integers, n and m (1 ≤ n, m ≤ 100), the number of rows and the number of columns in the grid, respectively.

The next n lines each contain m integers. In particular, the j-th integer in the i-th of these rows contains gi, j (0 ≤ gi, j ≤ 500).

Output

If there is an error and it is actually not possible to beat the level, output a single integer -1.

Otherwise, on the first line, output a single integer k, the minimum number of moves necessary to beat the level.

The next k lines should each contain one of the following, describing the moves in the order they must be done:

  * row x, (1 ≤ x ≤ n) describing a move of the form "choose the x-th row". 
  * col x, (1 ≤ x ≤ m) describing a move of the form "choose the x-th column". 



If there are multiple optimal solutions, output any one of them.

Examples

Input

3 5
2 2 2 3 2
0 0 0 1 0
1 1 1 2 1


Output

4
row 1
row 1
col 4
row 3


Input

3 3
0 0 0
0 1 0
0 0 0


Output

-1


Input

3 3
1 1 1
1 1 1
1 1 1


Output

3
row 1
row 2
row 3

Note

In the first test case, Karen has a grid with 3 rows and 5 columns. She can perform the following 4 moves to beat the level:

<image>

In the second test case, Karen has a grid with 3 rows and 3 columns. It is clear that it is impossible to beat the level; performing any move will create three 1s on the grid, but it is required to only have one 1 in the center.

In the third test case, Karen has a grid with 3 rows and 3 columns. She can perform the following 3 moves to beat the level:

<image>

Note that this is not the only solution; another solution, among others, is col 1, col 2, col 3.

Solution (in PYTHON):

Solution:
import sys

n,m = [int(x) for x in raw_input().split()]
g = [[int(x) for x in raw_input().split()] for _ in range(n)]
gt = [[g[i][j] for i in range(n)] for j in range(m)]

def calc_best(mat):
    n = len(mat)
    m = len(mat[0])
    res = []
    mx,my = [],[]
    sol = [[0 for _ in range(m)] for _ in range(n)]
    mix = 555
    for i in range(n):
        mi = 555
        for j in range(m):
            mi = min(mi,mat[i][j])
        mx.append(mi)
        mix = min(mix,mi)
    for j in range(m):
        mi = 555
        for i in range(n):
            mi = min(mi,mat[i][j])
        my.append(mi)
    k = 0
    ok = True
    for i in range(n):
        k += mx[i]
        res.append((0,i,mx[i]))
        for j in range(m):
            sol[i][j] = mx[i]
    for j in range(m):
        dif = max(0,(my[j] - mix))
        k += dif
        res.append((1,j,dif))
        for i in range(n):
            sol[i][j] += dif
            if sol[i][j] != mat[i][j]:
                ok = False
#     for i in range(n):
#         for j in range(m):
#             print sol[i][j],
#         print

    if ok: return (k,res)
    return (-1,[])

k1,res1 = calc_best(g)
k2,res2 = calc_best(gt)

def printing(k,res,add):
    print k
    for (ind,j,val) in res:
        if (ind + add) % 2 == 0:
            for i in range(val):
                print "row", j+1
        else:
            for i in range(val):
                print "col", j+1

if k1 > -1 and k2 > -1:
    if k1 < k2:
        printing(k1,res1,0)
    else:
        printing(k2,res2,1)
elif k1 > -1:
    printing(k1,res1,0)
elif k2 > -1:
    printing(k2,res2,1)
else:
    print -1